1. Field of the Invention
The present invention relates to a display device that is capable of shifting different display contents on the identical display surface of the display device.
2. Description of the Related Art
A display device of this kind is disclosed in Japanese patent laying-open publication No. 2001-100679. This display device has a first printed area through which only blue light can pass and a second printed area through which only green light can pass, the other printed area to form a lightproof background, which are formed by printing on a rear surface of a transparent sheet that is illuminated from a rear side of the sheet by a first light source of blue light and a second light source of green light.
The above known conventional display device, however, encounters a problem that a display device requires a high-precision printing process, resulting in a high manufacturing cost, because all the areas are printed on one side of the sheet and the three printed areas are formed adjacently to one another. In addition, in a case that the adjacent printed areas are overlapped with each other, their overlapping area parts stand out to impair display, while in a case that the adjacent areas have a gap between them, the light from the light sources passes through the gap, resulting in the deterioration of the display quality.
It is, therefore, an object of the present invention to provide a display device which overcomes the foregoing drawbacks and can obtain high display quality at a lower manufacturing cost and prevent light leakage without using a high-precision printing process.